Types of psychotropic drugs: uses and side effects

As we all know, the use of substances with properties that help to improve the symptoms of a disease or disorder It is a key element in medicine, being used to return the body to its state of natural balance.

In the case of psychological disorders, the presence of very diverse problems has generated the investigation of multiple treatment options, among them the pharmacological one.

What kinds of psychotropic drugs are there and what are they used for?

The fact that there are a large number of different symptoms and disorders has led to a wide variety of drugs to treat them, divided into different types of psychotropic drugs. None of these categories is, in itself, better than the rest, and its usefulness will depend on each case. However, clinical psychologists and psychiatrists must know them all to offer the best possible treatment to their patients.

Let's proceed to see below the different types of psychotropic drugs that exist in reality.

1. Neuroleptics / antipsychotics

Used primarily as a method of controlling psychotic seizures

, This group of psychotropic drugs were formerly called major tranquilizers due to the level of sedation that their first versions caused. There are different groups within this conglomerate, exerting an effect mainly on the transmission of dopamine in distant brain regions.

Among the neuroleptics we can find:

1.1. Classic / typical antipsychotics

The mechanism of action of these substances is based on blocking the dopamine receptors (specifically the D2 receptors) of the mesolimbic pathway, a blockage that causes a cessation of the positive symptoms of the schizophrenia Y psychotic disorders (hallucinations, delusions, etc.).

However, the action of this type of medication does not only occur in the mesolimbic circuit, but affects the rest of the pathways dopaminergic, being able to cause secondary effects in different facets such as movement (for example tremors, dyskinesias delays, restlessness or low spontaneity) or reproduction (emission of milk from the breasts regardless of sex or amenorrhea between others).

What's more, these medications have very little effect on negative symptoms (lack of logic, poor language, motor and mental slowness), its effect being practically non-existent in this sense. Within this group can be found chlorpromazine, haloperidol or pimozide, among others.

1.2. Atypical antipsychotics

Atypical antipsychotics were synthesized with the aim of producing an improvement in negative symptoms and reducing side effects due to the involvement of other pathways. This type of neuroleptic works by blocking dopamine and serotonin, achieving with the blocking of the second to eliminate the secondary effects of the blocking of the first.

Likewise, given the greater number of serotonin receptors in the cortex and the fact that it acts as an inhibitor of dopamine, inhibition of dopamine causes a increased action of dopamine in the mesocortical areas, which causes improvement in symptoms negatives. In spite of everything, they can present some side effects such as hypotension, tachycardia, dizziness or sedation. In the case of clozapine, there is also the risk of agranulocytosis, an alteration in the count of red and white blood cells that can be fatal if not controlled.

Within this group we find clozapine, risperidone, olanzapine, quetiapine, sulpiride and ziprasidone. Since they belong to different families, they can have a greater or lesser effect on certain disorders, working not only for psychotic disorders but for others such as tic disorders, autism, TOC Y mood disorders.

2. Anxiolytics and Hypnotic-sedatives

The presence of anxiety problems is a frequent phenomenon in today's society, being the most frequent type of disorders. In order to combat it, anxiolytics have been generated.

This type of psychotropic drug acts by exerting a depressant effect on the nervous system, causing a decrease in the level of activity of the person. They generally act on the GABA hormone, enhancing its inhibitory action. Some types of psychotropic drugs included in this classification are used as sedatives, to facilitate sleep, while others are used to simply achieve physical relaxation and mental.

Within this group we can find the following subtypes:

2.1. Barbiturates

This group of psychotropic drugs were the most popular until the discovery of benzodiazepines at the time of treat anxiety. However, the risk of these drugs is that they have a high capacity to cause dependence, and poisoning by overdose and even death is not uncommon. Also in the long term they could cause neurological damage.

2.2. Benzodiazepines

The discovery of this type of psychotropic drugs greatly helped the treatment of anxiety disorders, presenting a series of benefits that have been made at present by the most commercialized psychotropic drugs for anxiety. Specifically, in addition to an immediate effect, they present less risk to health than barbiturates, producing fewer side effects, being less addictive and causing less sedation.

In addition to their anxiolytic effect, benzodiazepines are used as sedatives and even as anticonvulsants. However, in long treatments they can generate dependence as well as abstinence after the cessation of their consumption, so that medical prescriptions must be strictly followed and their intake and withdrawal.

It is a type of substance that favors the inhibitory function of GABA, being indirect agonists of this neurotransmitter. Although they are nonspecifically distributed by whole brain, the bark and the limbic system It is where they present the greatest performance.

Within the benzodiazepines there are also various types, depending on whether they have long action (they require more time to take effect but it lasts a long time). greater than that of the rest), intermediate or short (immediate action and of short duration, ideal for panic attacks), that is, depending on the half-life of the substance in the organism.

Some examples of benzodiazepines are the well-known triazolam, alprazolam, lorazepam, clonazepam or bromazepam (better known by its brand name, Lexatin).

2.3. Short-acting sedative-hypnotic

Zaleplom, Zolpidem and Zopiclone are the names of three drugs that, like benzodiazepines, act as GABA agonists. The main difference with benzodiazepines is that while they act on all GABA receptors, the hypnotics only act on receptors linked to sleep, not affecting cognition, memory or function muscular.

2.4. Buspirone

This psychoactive drug is used especially in cases of generalized anxiety disorder. Its mechanism of action focuses on serotonin, being an agonist of it. Thus, it is one of the few anxiolytics that are not related to GABA receptors. It does not cause dependency or withdrawal. However, it has the disadvantage that the effect of this substance can take more than a week to take effect.

3. Antidepressants

After anxiety disorders, mood disorders are some of the most prevalent in the general population, especially in the case of depressions. To treat this problem we have this class of psychotropic drugs, which propose different alternatives. Of course, the exact mechanism by which they are useful to treat certain disorders is not yet known, and they are not only useful for mood alterations.

In any case, as with any of the other types of psychotropic drugs, antidepressants can only be used for medical indications. The fact that they act mainly on the mood does not mean that their influence on the brain does not have considerable risks.

3.1. MonoAmino Oxidase Inhibitors (MAOS)

The first antidepressants to be discovered, this type of psychotropic drug was found accidentally while looking for a remedy against tuberculosis. Its operation is based on the inhibition of the enzyme monoamine oxidase, which is responsible for normally to remove excess monoamines (specifically serotonin, dopamine, and noradrenaline).

This type of antidepressant tends not to be used as the treatment of choice, being reserved for cases that do not respond to other drugs. The reason for this is that they present a high risk of hypertensive crisis, being necessary an exhaustive control of its administration and having control that certain foods that contain tyramine or are rich in protein are not consumed (such as chocolate, dried fish, cheese, coffee, beer…). It also has other side effects such as possible anorgasmia or weight gain.

Within the MAOIs can be found Irreversible and Non-Selective (their function is to completely destroy the MAO enzyme) and Reversible and Selectives that only inhibit the function of MAO without destroying it, so if there is a real excess of monoamines the enzyme could function. Examples of MAOIs would be Isocarboxazid and Moclobemide.

3.2. Tricyclic and tetracyclic

Found while investigating the creation of neuroleptics, This type of psychotropic drug was the most widely used for the treatment of depression until the discovery of the SSRIs. Its name comes from its ring-shaped structure. Its action is based on inhibiting the reuptake of both serotonin and norepinephrine, with which these hormones remain for longer in the synaptic space, having a longer effect. The effects of these drugs begin to show after two or three weeks.

However, apart from their effect on serotonin and norepinephrine, they also affect other hormones, being antagonists of acetylcholine, histamine and blocking some receptors of noradrenaline. Therefore, they can cause antihistamine and anticholinergic effects (dry mouth, constipation, blurred vision ...). They can also cause death by overdose, so they must be regulated with special caution.

Some famous tricyclic antidepressants are imipramine (used in addition to depression in anxiety disorders and parasomnias) or clomipramine (also used as a treatment for OCD and anorexy).

3.3. Specific Serotonin Reuptake Inhibitors (SSRIs)

SSRIs are a type of psychotropic drug that is characterized by, as its name indicates, inhibit serotonin reuptake specifically. That is, to prevent serotonin from being reabsorbed so that it is more available and its presence in the brain is prolonged, without affecting other neurotransmitters.

In this group of psychotropic drugs we find fluoxetine (the well-known Prozac), paroxetine, sertraline, fluvoxamine, citalopram, and escitalopram.

It is the type of antidepressant with the highest level of safety and fewer side effects, being first-line treatment in many cases, and not only for major depression but also for other disorders. Specifically, they are the pharmacological treatment of choice in OCD, as well as in eating disorders (fluoxetine is the most effective in cases of bulimia).

3.4. Selective Noradrenaline Reuptake Inhibitors

Like the SSRIs, the performance of this type of drug is based on inhibit the reuptake of a hormone so that it has a greater presence at neuronal synapses, in this case norepinephrine being the neurotransmitter in question. Reboxetine is the most relevant drug in this regard.

3.5. Dual Serotonin and Noradrenaline Reuptake Inhibitors

It acts in the same way as tricyclics, but with the difference that they only affect the neurotransmitters on which they are intended to act. In other words, they are specific, which eliminates a large part of the side effects. The example of a drug of this type available today is venlafaxine.

4. Mood Stabilizers / Eutimizers

Another major mood disorder is bipolar disorder. In order to maintain a balanced and stable state of mind, two basic types of psychoactive drugs are also available:

4.1. Lithium salts

Although it is proposed that it produces an alteration of the G protein that modulates the transmission of messages in neuronal synapses, the mechanism of action of this type of psychotropic drug is not yet fully known. Despite the exact ignorance of why, this medicine has shown high efficacy in treating manic episodes and keeping mood stable.

However, it has the disadvantage that the difference between the amount necessary to produce an eutimizing effect and the necessary for intoxication is very narrow, being essential the control by analysis of the level of lithium in blood. It can also produce some side effects such as diarrhea, acne, tremors, hair loss or cognitive loss, with which there may be a certain resistance to the treatment.

4.2. Anticonvulsants

While these medications were developed to control seizures in epilepsy, studies have shown that they are also highly effective in treating bipolarity.

Its operation is based on favoring the action of GABA and reducing that of glutamate. Valproic acid, carbamazepine and topiramate are mainly used.

Bibliographic references:

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